1. Field of the Invention.
The invention generally relates to conductors and insulators. More specifically, the invention relates to boxes and housings, especially to covers or face plates for termainal housings. The invention also generally relates to receptacles, and more specifically to the outlet or junction box type, with closure. A termainal block cover is disclosed that is especially adapted for use with terminal blocks of the type employed with telephone systems.
2. Description of the Prior Art
The terminal block is a widely used commodity in commercial telephone installation equipment. The block usually is an elongated rectangle that is formed from nonconductive plastic material and supports a plurality of conductive wire terminators. The longitudinally elongated sides of the block carry fanning strips that aid in separating and supporting the many individual wires that are routed into the block. In a typical installation, one or more terminal blocks are mounted on a wall in vertical position, and telephone cables from a trunk system are routed to the blocks, where the individual wires of a trunk cable are individually attached to the separate terminating clips that are carried in the block. The terminating clip, also a well known device, is a metallic conductor that is capable of receiving and holding two or more separate wires in electrical contact with each other. Each separate terminating clip typically includes a distinct clip portion corresponding to each wire, all such clip portions being in electrical contact with each other, such that all wires that are to be connected via the same clip can be individually installed or removed. Thus, in incoming trunk cable containing, for example, twenty five wire pairs, will have its wires fanned out and attached to first clip portions of fifty individual terminating clips, which may be contained in a single terminal block. Then, these trunk system wires are readily available for individual connection to local telephone equipment by attachment of wires from the local system to the second clip portions of the terminating clips. The block, therefore, is an interface between trunk cables and local equipment, enabling the installer to easily and quickly identify the wire pairs of the trunk cable and make appropriate attachment to local system wires.
Terminal blocks are covered for protection of the terminating clips and wires and to prevent accidental short circuits or other damage to the internal connections. It is quite important that the covers be employed, as the terminal blocks often must be mounted in closets or storage rooms, where various types of mistreatment and contact with foreign matter is common. At the same time, the terminal block may be subject to frequent rewiring and must be available to telephone service technicians. Thus, the covers should be readily removable so that technicians can locate relevant wire pairs. Still another function of the cover is to provide a location for technicians to record informtion about the connections and equipment. Thus, the requirements of a good cover include firm, easy fastening to the block; rapid opening for inspection; and an ability to be written upon.
Various types of terminal block covers are known. For example, U.S. Pat. No. 3,836,826 discloses a snap-on cover that includes a means for preventing longitudinal sliding. U.S. Pat. No. 3,966,074 discloses a terminal block cover that has fastening elements that are adapted to engage parts of the fanning strips on the edges of the terminal block.
While these types of covers are excellent in their protective functions, it is often desirable to be able to open terminal block covers while retaining the cover on the block. This prevents mixing covers, which is especially important when information concerning the connections is written on the cover. Also, a semi-permanently attached cover is less subject to loss or theft and is more likely to be reinstalled after removal. Still another desirable feature is to have a cover that can be indexed to the terminal block by its position, so that information on the cover can be related to specific terminals within the block.
Another type of cover in present use, but for which no patent is known, employs a face plate of molded plastic with a plastic "living hinge" at one edge. The hinge is connected to a side plate that carries spring hooks that engage a plurality of the fanning strips on the sides of the terminal block. The opposite edge of the face plate carries another side plate, which includes a friction latch that engages over the fanning strips. This type of cover can be opened on its hinge and may stay attached to its terminal block even when open. Also, it may be removed from the terminal block by lateral pulling. Removal may be difficult, however, depending upon the amount of lateral space that is present. Also, the life of a plastic living hinge is short due to the quantity of fire-retardant that is required in plastic materials used in electrical service. A further disadvantage is that the side plate carrying the spring hooks largely covers the fanning strips on the hinge side of the terminal block, preventing the technician from wiring through that side of the block without entirely removing the cover.
Consequently, it would be desirable to have a hinged cover of improved hinge durability. Also, it would be desirable to have a cover that is capable of being removed even in close-mounting situations. In addition, after such a cover is removed, it would be desirable to have its position indexed to the terminal block, so that it will be reinstalled in an indentical location. Further, it would be desirable to have an attachment between the cover and terminal block such that substantially all of the fanning strips on the terminal block are accessible. In those instances when it is necessary to entirely remove the cover from the block, it would be desirable to have a cover that retains its indexing.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the terminal block cover of this invention may comprise the following.